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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: acidjack on December 05, 2010, 12:03:23 PM

Title: Using multi-band compressor in Audacity?
Post by: acidjack on December 05, 2010, 12:03:23 PM
Running Audacity for Mac, current or relatively current version.  Apple has a multi-band compressor plugin.

There are three crossovers with different frequencies available. It seems to default to a low bass (200Hz), low-midrange (900Hz) and midrange (4000Hz)

There are also settings for "pre-gain" and "post-gain".  What is that intended to do?  I understand what gain is, I just don't understand how that applies to this.

Then there are settings for each of the crossover freqs:
Threshold
Headroom
EQ

I understand that "threshold" is going to be the normal compressor threshold- the threshold at which the compressor starts to activate.  But what do "EQ" and "headroom" mean, in this context?  The EQ is just a slider, from -20 to 20dB.  Headroom goes from .01 to 40dB

I'm trying to compress a board feed with a bunch of loud snare hits.  It seems to be working well to my ears, but I'd like to know what I'm actually doing....
Title: Re: Using multi-band compressor in Audacity?
Post by: morst on December 15, 2010, 10:03:15 PM
That's a toughie to explain, and it doesn't help that the interface on the apple plugin sucks! If the damn thing had mutes on the three bands, you could get a much better listen to what it's doing. Shit, if Audacity let you adjust effects in real time, and click the bypass button on & off, I'd still be happy to use it! 'Tev.
Title: Re: Using multi-band compressor in Audacity?
Post by: page on December 15, 2010, 10:06:31 PM
That's a toughie to explain, and it doesn't help that the interface on the apple plugin sucks! If the damn thing had mutes on the three bands, you could get a much better listen to what it's doing. Shit, if Audacity let you adjust effects in real time, and click the bypass button on & off, I'd still be happy to use it! 'Tev.

It's my only beef, I'd make a donation to them if they would just implement the ability to route audio to a VST/AU in real time while adjusting settings. It is quite possibly the only piece of that program that I don't like. Everything else I've either gotten used to, or is better then other mac editors (their hard/soft limiter is implemented differently, and can be really handy to play with on occasion).
Title: Re: Using multi-band compressor in Audacity?
Post by: acidjack on December 16, 2010, 11:01:01 AM
^^ Agree, I do dislike that limitation.  I find that I end up just applying an effect to one track, listening to it, undoing it, re-applying it, until I decide.  Not very efficient.
Title: Re: Using multi-band compressor in Audacity?
Post by: Patrick on December 16, 2010, 12:01:59 PM
The non-real time effects in Audacity prevents ANY surgical processing. Completely useless to me and I'm surprised that someone hasn't fixed this issues after all these years.

I will say that Audacity's noise/click removal plug ins are quite good and I've used the program for this purpose when editing NPR stories.  I'll fly a clip into Audacity to remove some horrible noise, then back into Pro Tools for mixing.  I find the Audacity plug in works so much easier than using the pencil tool in Pro Tools.  Very useful!
Title: Re: Using multi-band compressor in Audacity?
Post by: morst on December 20, 2010, 11:05:52 PM
^^ Agree, I do dislike that limitation.  I find that I end up just applying an effect to one track, listening to it, undoing it, re-applying it, until I decide.  Not very efficient.
Prezactly. When I started using Digital Performer recently, I was blown away by the feeling of "turning a knob" and having it affect the sound in real time. Why, that's just like what it feels like to mix live sound or in a studio. BOIIING! So all those years of being a purist and not tampering with my masters one bit, worked fine in Audacity. But now I actually have tools I can use to hear, with my ears, if I'm improving the sound by making a change! Creative control returns when you have tools that allow you to work comfortably. Audacity is a brilliant hack, but you get what you pay for, in so many ways. Ok, in Patrick's case, you can get more than you pay for if you're smart about using the best tool for the job.
Title: Re: Using multi-band compressor in Audacity?
Post by: andromedanwarmachine on December 21, 2010, 08:27:20 AM
Do you know- I've read this a couple of times now and I think it's probably quite simple;

Is it not just (to answer the core question of this thread) an adjustment for incoming and outgoing signal level?

It's perhaps a bit unnecessary, but that is what is going on I think.

I just got exposed to Audacity the other night actually for the first time- is it a free download from somewhere or do you have to pay money for it? Seems like a lot for free...

JimP
Title: Re: Using multi-band compressor in Audacity?
Post by: rjp on December 21, 2010, 09:53:02 PM
Audacity is free.

http://audacity.sourceforge.net/
Title: Re: Using multi-band compressor in Audacity?
Post by: andromedanwarmachine on December 23, 2010, 06:14:38 AM
Oh, that's tremendous!

Thanks for that rjp...

JimP
Title: Re: Using multi-band compressor in Audacity?
Post by: morst on December 26, 2010, 05:00:19 PM
Is it not just (to answer the core question of this thread) an adjustment for incoming and outgoing signal level?
D'oh! Nice focus adjustment there. Yeah, Pre & Post gain are there so you can twiddle your levels more carefully. If you increase pre-gain too much, it will cause you to hit the threshold, and therefore, give you more of the effect. If you're basically trying to use this as a mastering plugin, you will probably want to avoid too much pre-gain. You don't want to cause so much effect as to color the output, I don't think. Post gain is more of a handy adjustment when you're working on individual tracks of a multi-track project, I would think. Not much purpose to it if you're using the effect to push levels up to nearly 0dB fs already.